Introduction to IoT Week-3: SUMMARY
We’re thrilled to have you back as we continue our exploration of the Internet of Things. Week 3 promises even more enlightening insights and discoveries, building on the knowledge we’ve gained so far. Whether you’re a seasoned IoT enthusiast or just starting, there’s something exciting in store for everyone.
Let’s dive deeper into the world of IoT, embrace new concepts, and continue our journey of discovery together. Stay engaged, stay curious, and let’s make this week of learning a memorable one!
WirelessHART: It is the latest evolution of the Highway Addressable Remote Transducer (HART) Protocol, extends the capabilities of networked smart field devices by offering a wireless implementation, making HART more cost-effective and accessible. It is recognized for encompassing the most field devices in any field network, gains flexibility through WirelessHART, allowing devices to be placed in previously challenging locations, such as the top of a reaction tank or inside pipes. The main difference between wired and wireless HART lies in the physical, data link, and network layers, with wired HART lacking a network layer.
The HART Physical Layer, operating in the 2.4 GHz ISM band, derives from the IEEE 802.15.4 protocol, utilizing 15 channels to enhance reliability. The Data Link Layer ensures collision-free and deterministic communication through super-frames and TDMA. These super-frames control transmission timing, incorporating channel hopping and blacklisting to boost reliability and security.
The Network and Transport Layers collaboratively handle routing, session creation, and security, relying on mesh networking in WirelessHART, with each device capable of forwarding packets from others. The Application Layer handles communication between gateways and devices, executing commands and generating responses, without differentiation between wireless and wired HART.
Congestion control in HART involves channel switching and synchronized transmissions, minimizing collision risks, while the WirelessHART Network Manager supervises nodes, ensuring collision-free and timely packet delivery. It also manages network security and node authorization, maintaining network integrity.
Near Field Communication (NFC): It is a close-range communication technology that stems from radio-frequency identification (RFID). It is designed for interactions between devices in close proximity to each other, making it highly convenient for various applications. There are two primary types of NFC devices: passive and active.
Passive devices contain information readable by other devices but can’t initiate reads themselves, while active devices can both collect and transmit information.
Working Principle of NFC Tags: The working principle of NFC relies on magnetic induction, where a reader generates a magnetic field through an electric current, which bridges the physical space between devices. The receiving device uses a similar coil to convert this field back into electrical impulses, facilitating data communication. Passive NFC tags harness the reader’s energy for encoding their response, while active (or peer-to-peer) tags have their own power source, offering versatile communication capabilities.
Bluetooth: It is a wireless technology, a short-range communication solution designed to replace cables connecting portable devices. It prioritizes security and operates in the unlicensed ISM band at 2.4 to 2.485 GHz. Using spread spectrum hopping at a rate of 1600 hops per second, Bluetooth offers varying data rates: 1Mbps for Version 1.2 and 3Mbps for Version 2.0. The range of Bluetooth devices depends on their class: Class 3 radios have a 1-meter range, Class 2 radios in mobile devices have a 10-meter range, and Class 1 radios in industrial applications extend up to 100 meters.
In Bluetooth technology, the Baseband serves as the physical layer, managing physical channels, links, and providing services like error correction, data whitening, hop selection, and Bluetooth security. It oversees both asynchronous and synchronous links, handling packets, paging, and inquiry processes.
The Logical Link Control and Adaptation Protocol (L2CAP) operates above the Baseband Protocol in the data link layer. L2CAP is responsible for multiplexing multiple logical connections between devices, offering connection-oriented and connectionless data services. It provides protocol multiplexing capabilities, segmentation and reassembly operations, and group abstractions.
Radio Frequency Communications (RFCOMM) serves as a cable replacement protocol, emulating a virtual serial data stream. It enables binary data transport and mimics EIA-232 (formerly RS-232) control signals over the Bluetooth baseband layer. RFCOMM offers a reliable data stream, similar to TCP, supporting up to 60 simultaneous connections between Bluetooth devices.
The Service Discovery Protocol (SDP) facilitates applications in discovering available services and their features within the Bluetooth environment. It adapts to dynamic changes in service quality and operates over a reliable packet transfer protocol, following a request/response model.
In Bluetooth communication, devices create small wireless networks known as Piconets. These ad-hoc networks allow devices to act as masters or slaves, with provisions for role-switching. Piconets can range from simple point-to-point configurations with one master and one slave to more complex setups with up to seven slaves surrounding a single master. The master manages transmission control by dividing the network into time slots using time division multiplexing.
Features of Piconet: The timing and frequency hopping sequence of devices in a Piconet are determined by the clock and unique 48-bit address of the master. Each Piconet device can maintain up to seven simultaneous connections with other devices, and it can communicate with multiple Piconets concurrently. Piconets are formed dynamically as Bluetooth-enabled devices enter and exit them, with no direct connection between the slaves. All connections are either master-to-slave or slave-to-master, with slaves transmitting once polled by the master. A device can participate in multiple Piconets, acting as a slave in one and a master in another but not as a master in more than one. Devices in adjacent Piconets bridge connections, forming a physically extensible communication infrastructure known as Scatternet.
Bluetooth technology finds applications in a wide range of devices and systems, including audio players, home automation, smartphones, toys, hands-free headphones, and sensor networks. Its versatility and adaptability make it suitable for diverse IoT applications.
Z-Wave: It is a home automation communication protocol, utilizes RF signaling and control while operating at 908.42 MHz in the US and 868.42 MHz in Europe, supporting mesh network topology with a capacity for 232 nodes. It employs GFSK modulation and Manchester channel encoding. Each network is managed by a central network controller device, featuring one Home (Network) ID and multiple node IDs for the devices. Devices with different Home IDs cannot communicate with each other. The Network ID is 4 bytes in length, while the Node ID is 1 byte.
Z-Wave uses a source-routed network mesh topology with one primary controller. Devices communicate within range, and when out of range, messages are routed through other nodes to circumvent obstructions created by household appliances or layout. This process, called Healing, helps overcome radio dead spots. Z-Wave relies on a source-routed static network, excluding mobile devices and focusing on static ones.
ISA 100.11A: It was developed by the International Society of Automation, primarily designed for large-scale industrial complexes and plants, boasting over 1 billion devices in use. This protocol supports both native and tunneled application layers and offers various transport services, including ‘reliable,’ ‘best effort,’ and ‘real-time.’ Its network and transport layers are based on TCP or UDP/IPv6, while the data link layer supports mesh routing and frequency hopping. The physical and MAC layers rely on IEEE 802.15.4, and it permits various topologies, such as star/tree and mesh, as well as networks, including radio links, ISA over Ethernet, and field buses.
Key features: It include flexibility, support for multiple protocols and applications, reliability through error detection and channel hopping, determinism with TDMA and QoS support, and robust security. Security is integral to the standard, with built-in authentication and confidentiality services. A network security manager handles key distribution, and twin data security steps are implemented in each node, with the data link layer encrypting each hop and the transport layer securing peer-to-peer communications.
Wireless Sensors Networks: They are networks comprising numerous sensor nodes densely distributed in an area. These nodes work collaboratively to monitor their environment and convert the collected measurements into digital data. Given the limited radio transmission range of these nodes, intermediate nodes function as relays, facilitating data transmission to a central sink node via multi-hop paths.
Sensor nodes: They are multifunctional devices used in various applications, and their number depends on the specific use case. They have short transmission ranges, run on battery power, and are equipped with operating systems like TinyOS. These nodes come with constraints such as small size, extremely low power consumption, operation in unattended and dense environments, cost-effectiveness, autonomy, and adaptability to the surroundings.
Some common applications of sensor nodes include measuring temperature, humidity, lighting conditions, air pressure, soil composition, noise levels, and vibrations.
Challenges in wireless sensor networks (WSNs) include scalability, quality of service, energy efficiency, and security. Scalability involves providing service for a large number of nodes, while quality of service guarantees are essential for bandwidth, delay, and reliability. Energy efficiency is crucial due to battery-powered nodes, and security is vital to protect against malicious attacks.
In wireless ad hoc and sensor networks, node cooperation can vary from total to no cooperation, impacting network performance. Node behavior can range from normal operation to failed, badly failed, selfish, or malicious behavior.
Dumb behavior, a temporary issue caused by environmental conditions, can disrupt the network. Detecting and re-establishing connectivity with dumb nodes is essential. Information theoretic self-management optimizes transmission rates for energy efficiency.
Social sensing is used for duty cycle management in monitoring rare events, but it may not effectively distinguish rare events from regular ones, leading to ineffective sensing under rare event scenarios.
Thank you for joining us in Week 3 of our IoT journey. By exploring the fascinating world of wireless communication protocols, we’re getting closer to unlocking the full potential of the Internet of Things. Stay tuned for more exciting insights in the weeks to come, and congratulations on your continuous learning!
